Liquid crystal materials may change their optical properties if an electric field is applied across the liquid crystal material. As such, liquid crystal materials may be used in a variety of optical devices, including displays, optical switches, and light modulators. For example, liquid crystal materials may be incorporated in a polarization control panel (PCP) to switch the polarization of the outgoing image light between two substantially orthogonal polarization states. Such PCPs are disclosed in commonly-assigned U.S. Pub. App. Nos. 2008/0316303 and U.S. application Ser. No. 12/853,274, both herein incorporated by reference.